All About Recycled Plastic Insulation (Should You Use It?)

A photograph of shredded plastic bottles ready for recycling with a drawing of a blue roll of recycled plastic insulation and a photo of three plastic bottles overlain. The plastic bottles are arranged in a circular "recycling symbol" shape. Across the top of the image are the words "All About Recycled Plastic Insulation (Should You Use It?)"

Insulation is a must-have feature for your home if you want to save on the cost of heating and cooling.

Recycled plastic insulation is one of the options you might have come across when looking for ways to insulate your home. However, before investing your hard-earned money in recycled plastic insulation, is it the best option for your home?

According to Energy Saver, insulation lowers heating and cooling costs by providing resistance to heat flow.

Therefore, one of the things you want to be sure of before using recycled plastic insulation is whether it provides excellent resistance to heat flow. If it does, you’ll be on the right path toward saving on your home’s energy costs.

In the rest of this article, I’ll discuss everything you need to know about recycled plastic insulation.

From this discussion, you’ll be able to know if you should use recycled plastic insulation in your home.

Let’s get started!

What Is Recycled Plastic Insulation?

A picture of a collection of plastic water bottles ready for collection for recycling. There are question marks, a drawing of a roll of loft insulation, and three green recycling arrows overlain.
Recycled plastic insulation is often made from waste plastic bottles, which are processed and turned into a high-performing insulation product.

Recycled plastic insulation is an environmentally-friendly insulation material made from recycled fiber from plastics. The plastics used for this insulation are sourced from post-consumer and post-industrial waste, such as containers, plastic bottles, and bags.

One of the ideas behind using recycled plastics for insulation is that plastics don’t have free electrons to conduct heat. Therefore, they are poor conductors of heat, a characteristic that meets the Energy Saver requirement that insulators must provide resistance to heat flow.

The fibers in the insulation also trap pockets of air that prevent heat flow, further enhancing the thermal properties of the recycled plastic insulation.

Moreover, plastics have become a menace contributing immensely to land and ocean pollution. For example, National Geographic notes that more than 8 million tons of plastic waste enter our oceans annually. Once in the ocean, these plastics cause suffocation and entanglement of marine species.

Therefore, recycled plastic insulation is a sustainable material that helps reduce plastic pollution by giving recycled plastics a new purpose. Consequently, you get to enjoy the insulation benefits while helping to save our environment!

The Making of Recycled Plastic Insulation

Recycled plastic insulation is made to precise standards to ensure high performance and safety. Here is the process involved:

Step 1: Collecting Plastic Waste

A smiling man with salt and pepper hair wearing an orange high-visibility jacket and blue work trousers collecting plastic for recycling in a blue-lidded waste bin. On the right of the image is a photograph of a collection of plastic water bottles similar to those you would expect to find inside the bin.
Collecting the plastic waste is just the beginning of its journey to being repurposed as recycled plastic insulation.

This is the first step in making recycled plastic insulation. Companies have collection centers from where they can source plastic waste.

Alternatively, they get plastic waste from waste management companies and local authorities.

Step 2: Sorting

Different plastic materials are collected together with other objects that may affect the quality of the recyclate. Therefore, sorting is necessary to remove foreign objects and categorize the different plastic materials for recycling.

Recycling companies use the following sorting techniques:

  • Manual picking
  • Magnet separator
  • OCC screening
  • Trommels
  • Optical sorting machines

Along with sorting, the materials are washed to remove dirt, labels, oil, and other contaminants that may affect the performance of the plastic insulation.

It’s worth mentioning that the best plastics for insulation are also segregated during the sorting process. Polyethylene terephthalate (PET) is one of the best plastic materials for this purpose.

Step 3: Grinding

A plastic recycling facility with a plastic granulator spitting shredded plastic particles out onto a rising conveyor belt for further processing.
The first step in recycling involves sorting and cleaning the waste material before it is shredded and ground using a plastic granulator (pictured).

After sorting, the plastic waste is transferred into shredding machines for grinding.

Grinding is done to reduce the plastic waste into smaller pieces or chips. This process is important because it ensures that the insulation performance is good and consistent.

After grinding, the plastic flakes are transferred to a drying machine to remove moisture.

Step 4: Melting and Extrusion

The plastic flakes are taken into the melting chamber for melting in preparation for extrusion. They are subjected to temperatures of about 400°C (752°F) for melting.

The molten material is transferred to extrusion machines, where it’s pushed through dies to produce strands of plastic material.

The strands are cut into small pellets in preparation for the next process.

Step 5: Forming the Insulation

The pellets are transferred to a mixing machine, where they are mixed with mineral fillers like glass fibers or other chemicals that enhance insulation properties.

Once the mixture is in place, it’s formed into insulation batts or rolls by pressing it into a specific shape for easy handling during installation.

Step 6: Quality Control

A woman working as a quality control technician in a recycled plastic insulation factory making notes in her notebook.
Quality control is important to ensure that the recycled plastic insulation performs to the high standard customers expect.

Finally, the insulation boards or rolls undergo testing to ensure high performance and safety.

Quality control includes testing for fire ratings, thermal conductivity, and durability.

Manufacturers also examine the boards or rolls to ensure they meet the required standards.

Once everything checks out, the recycled plastic insulation is ready for sale.

What Plastic Is the Best Thermal Insulator?

Polybenzimidazole (PBI) plastic is the best thermal insulator. PBI has excellent heat resistance properties and can withstand temperatures exceeding 400°C (752°F) with minimal deformation.

PBI has the highest heat resistivity compared to other engineered thermoplastics. Coupled with its excellent chemical resistance, PBI makes an ideal choice for thermal insulation.

Besides PBI, polyethylene terephthalate (PET) is also suitable for thermal insulation. This plastic is used in Supasoft loft insulation due to its extensional molecular chain configuration. The configuration has among the lowest heat conductivity in the plastic family.

Can You Make Insulation Out of Recycled Plastic?

You can make insulation out of recycled plastic because of its superior thermal insulation properties. Plastics have a very low thermal conductivity of approximately 0.2 W/mK, making them superior insulators.

Another feature that makes plastics suitable for insulation is their ability to trap air. The air trapped between plastic fibers creates a barrier that further prevents heat transfer.

However, if you decide to make insulation from plastic, you must use the right material for the best outcomes. Not all plastics are suitable for insulation. PET and PBI are the best choices for insulation.

Is Shredded Plastic a Good Insulator?

Blue shredded plastic in pellet form with a person's hands being dipped into it.
Shredded or pelletized recycled plastic makes good insulation thanks largely to the millions of tiny air pockets trapped within the material, reducing heat flow.

Shredded plastic is a good insulator because, besides plastics being a poor conductor of heat, shredded plastic has tiny air pockets. These air pockets slow heat movement through the material, making it suitable for insulation.

Shredded plastics are ideal insulators for warm water tanks and cavity walls. They can also be used as loose-fill, blown insulation for attics.

Overall, shredded plastic is an effective insulator that can save you money on energy bills while making your home more comfortable.

What Is the Most Eco-Friendly Insulation?

The most eco-friendly insulation materials include polystyrene, cellulose, sheep’s wool, cork, denim, and aerogel. These materials have minimal environmental impacts, are non-toxic, and are made from renewable resources.

Using these insulations lowers your home’s carbon footprint, conserves energy, and creates a cleaner environment.

Combining these eco-friendly insulations with sustainable building materials can help create a more sustainable and green home.

Using eco-friendly insulation is also a cost-effective approach that reduces your energy bills while increasing the value of your home. Thus, you get to enjoy healthy indoor air quality without any toxic fumes or chemicals.

What Is the Cheapest Way to Do Insulation?

A man wearing blue jeans, a blue sweater, protective gloves and a mask with his back to the camera installing fiberglass batts of insulation between wall studs. The insulation is almost complete with the very tops of the last five batts to be tucked in securely. There is a wooden steep ladder between the man and the camera.
Fiberglass batt insulation is the cheapest way to improve the thermal efficiency of your home. However, it is not the most eco-friendly form of insulation.

The cheapest way to do insulation is by using fiberglass batts. Fiberglass batts are made from inexpensive materials such as glass fibers and sand. Moreover, they are easy to install due to their lightweight nature.

Although they are cheap, fiberglass batts have excellent thermal resistance that contributes to their insulation capacity.

Due to their durability, your initial investment in this insulation can save you money in the long run.

Is Recycled Plastic Insulation Waterproof?

Recycled plastic insulation is waterproof because plastics are impervious to water. Polymer molecules in plastics have long fibers that repel water, making them waterproof and long-lasting.

The impervious nature of plastics makes plastic insulation suitable for outdoor structures like decks, patios, and balconies. It also makes it an excellent material for waterproofing roofs and walls.

Furthermore, plastic insulation is resistant to mold, mildew, and fungi growth due to its water-resistant nature. Therefore, recycled plastic insulation is the way to go if you’re looking for durable and affordable insulation that is also water resistant.

The Pros of Recycled Plastic Insulation

High Energy Efficiency

Recycled plastic insulation is energy efficient due to the very nature of plastics. Plastics are poor thermal conductors, making them good insulators that can reduce your energy bills.

Recycled plastic insulation also has tiny air pockets between polymer molecules, further slowing heat transfer. Thus, it’s an excellent choice for insulation that offers high energy savings.


Plastics are strong, durable, and corrosion-resistant. These features make plastic insulation a durable option that requires minimal maintenance. Once installed, the insulation can last for years without needing replacement.

Easy to Install and Remove

Recycled plastic insulation is lightweight, making it easy to install and remove. It doesn’t require special tools or expertise, making it a great DIY option.

Doing the installation yourself saves you money that would have otherwise been paid for expert installation.

Environmentally Conscious

Using recycled plastic insulation is an environmentally conscious choice. It helps reduce plastic waste in landfills and oceans, conserves energy, and reduces a household’s carbon footprint.

Moreover, using recycled materials reduces the need for virgin resources, lowering the environmental impact of insulation production.

Finally, recycled plastic insulation reduces greenhouse gas emissions associated with the production of traditional insulation materials.

The Cons of Recycled Plastic Insulation

Potential Toxicity

Recycled plastic insulation may contain toxic chemicals from the original plastic.

Some chemicals, such as dioxins and plasticizers, can harm your health if they enter the indoor air.

Therefore, it’s important to check the safety ratings of recycled plastic insulation before use.


Recycled plastic insulation is more expensive than fiberglass batts due to its complex production process.

However, its long-lasting nature makes it a cost-effective option in the long run.

Highly Susceptible to Fire

A picture of a house attic with recycled plastic insulation installed. There are drawings of flames and a warning sign overlain.
Recycled plastic insulation is more susceptible to fire than other forms of insulation, such as rock wool. It also emits toxic gases when burnt.

Plastics are made of synthetic polymers derived from petroleum oil. Naturally, petroleum is highly flammable, meaning plastics are highly susceptible to fire.

The susceptibility of plastic to fire makes recycled plastic insulation unsuitable for areas with high fire risk.

Final Thoughts

Recycled plastic insulation offers a compelling solution to reduce environmental impact and non-renewable energy use.

By reducing waste and energy consumption, recycled plastic insulation helps mitigate the impact of climate change while keeping your home warm and cozy.

However, as with any material, it’s essential to consider its benefits and drawbacks before use.

Sheep’s wool insulation is another option you might consider. However, is it susceptible to water damage? Check out this article, where we discuss sheep’s wool insulation and water damage.

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